Container blank delivery mechanism



May 27, 1952 H. K. WETHE ETAL CONTAINER BLANK DELIVERY MECHANISM 5 Sheets-Sheet 1 Filed Aug. 17, 1949 INVENTORS HARRY K. WETHE ROBERT H. DUNCANSON BY w ATTORNEY H. K. WETHE ETAL CONTAINER BLANK DELIVERY MECHANISM 5 Sheets-Sheet 2 INVENTORS HARRY K. WETHE ROBERT H. DUNCANSON AT TORNE Y May 27, 1952 Filed Aug. 1'7, 1949 May 27, 1952 H. K. WETHE ETAL 2,598,150

CONTAINER BLANK DELIVERY MECHANISM Filed-Aug. 17, 1949 I 5 Sheets-shat 3 HARRY K. WETHE B T H DUNCANSON ATTORNEY y 27, 1952 H. K. WETHE ETAL 2,598,150

' CONTAINER BLANK DELIVERY MECHANISM Filed Au 17, 1949 5 Sheets-Sheet 4 FIG. 5

FIG. 6

FIG. 7 I

FIG. 8

INVENTORS HARRY -K. WETHE ROBERT H. DUNCANSON w [aw 5% A T TORNE Y May 27, 1952 H. K. WETHE ET'AL 2,598,150

CONTAINER BLANK DELIVERY MECHANISM Filed Aug. 17, 1949 5 Sheets-Sheet 5 l INVENTORS HARRY K. WETHE ROBERT H. DUNCANSON AT TORNE Y Patented May 27, 1952 CONTAINER BLANK DELIVERY MECHANISM Harry K. Wethe and Robert Horace Duncanson,

Minneapolis, Minn., assignors, by mesne assignments, to Package Machinery Company, East Longmeadow, Mass., a

chusetts corporation of Massa- Application August 17, 1949, Serial No. 110,712

Claims.

The invention relates to improvements in machines for removing and delivering a single sheet from a stack of sheets, and more specifically to machines where carton blanks are removed from the bottom of a stack, one at a time, in rapid succession and delivered to a machine for folding the blanks into container form.

Sheets or blanks used to form containers are usually of heavy paper, flbreboard, lamination of paper, or similar material. In a machine of the type in which the present invention is embodied, the sheets are placed in stacks in a vertical or inclined position on the machine, the sides of the stack being supported by a rack, and the bottom of the stack being supported by holders. Single sheets are withdrawn from the stack by a suction cup gripping the lowermost sheet and pulling it from the holders while the remainder of the stack remains supported by the holders.

Changes in temperature and moisture in the air cause curving or warping of the stacks. Also the weight of the stacks in the rack causes bending of the lower sheets in the stack, the bending becoming less as the size of the stack is reduced. This warping and bending is the cause of difliculty in that the whole stack will slide past the holders, the suction cups refuse to grip a curved surface, the delivery device will not deliver and position accurately the warped blank, and the container forming mechanism will not satisfactorily operate on warped sheets. The provision of a device which will avoid these and other difficulties is among the objects of the present invention.

One object of the invention is to provide a device which will satisfactorily operate to remove warped or bent sheets from a stack of sheets one at a time, flatten the blanks and deliver them accurately positioned on a delivery table of a machine for forming the sheets into containers.

A further object of the invention is to provide a mechanism for removing and delivering bent or warped sheets from stacks which will operate with stacks of sheets having diiferent degrees of curvature or warpage.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings in which:

Figure 1 is a partial perspective view of a complete carton forming machine.

Fig. 2 is 'a perspective view of the blank delivery mechanism.

Fig. 3 is a side elevation of the blank delivery' mechanism.

Fig. 4 is a perspective of the device for supporting the blanks in the rack.

Fig. 5 is a side elevation of the mechanism for delivering and flattening the blanks as the carriage begins to move forward.

Fig. 6 shows a subsequent position of the carriage of Fig. 5 as it moves forward.

Fig. '7 shows the carriage in a still more forward position.

Fig. 8 shows the carriage of the forward position.

Fig. 9 is a side elevation of the vacuum control cam mechanism.

Figs. 10a and 10b are perspective views of the vacuum cup arm showing various settings of the arms and cups for accommodating different degrees of blank warpage; and

Fig. 11 is a perspective of the blank depressor member.

The mechanism as shown in Fig. 1 removes a single fiber sheet or carton blank from a stack of blanks and flattens the blank and delivers it, positioning it accurately on a delivery table of a forming machine where the machine forms the blank into container shape by a series of folding operations. The present invention embodies only the mechanism for holding the stack of blanks, removing a single sheet from the blank, flattening the blank, and delivering it to the delivery table. The mechanism for holding, flattening, and delivering blanks is suitable for adoption with any mechanism which requires the delivery of single sheets from a stack. The device is shown and is especially advantageous as used in connection with a carton forming machine.

Referring to Fig. 1, the container forming unit and the drive mechanism will be described. The numeral l0 denotes a forming mandrel which is carried by a downwardly curved arm 12 vertically slidable on a pair of guide bars I 4. The mandrel and arm are vertically reciprocated by a pitman l6 which is eccentrically connected to a crank wheel [8 mounted on the drive shaft 20. A sprocket 22, which is operated by a chain 24 and second sprocket 26 leading through a second shaft 28 and pulleys 30 and 30 and a belt 34 to the driving motor 36, provides the operation of the drive shaft. The working assembly including the shaft bearings is suitably mounted in the supporting framework 38. Positioned beneath the mandrel is a delivery table 40 having in its center a container forming well 42 bounded on the four sides by the forming dies 44. .On the platform is an abutment 48 which provides a stop for positioning the blank. In operation a blank is accurately positioned by the delivery mechanism over the well on the delivery platform. As the mandrel is caused to descend by the action of the pitman and crank, the blank is pushed downwardly into the well and the dies progressively fold up the edges of the blank against the mandrel to form the blank into container shape. At the bottom of the de-" scending stroke, the container has been formed, and as the mandrel begins to ascend the edges of the container catch on rabbets (not shown) in the sides of the well and the container is stripped from the mandrel and left between the dies. On forming the next succeeding carton the descent of the mandrel will move a new container blank downward through the dies and push out the previous container to drop on the conveyor trough 48 to be carried laterally away by the chain 50 moving along the bottom of the trough. The chain is carried over a sprocket .52 at the near end of the conveyor trough and a sprocket 5.4 at the far end which is mounted on a shaft being driven by means of sprockets 56 and 58, and a chain 60 from the drive shaft.

The present invention is embodied in the device which serves to remove the single blanks from the stack,.fiatten them and accurately position them one at a time in rapid succession over the forming well under the mandrel.

The stack of blanks 62 is supported in an inclined position in a rack 54 bolted to vertical frame members 66 as shown in Figs. 2 and 3. The rack forms a lateral support for the sides of the stack and is easily accessible for the insertion of fresh blanks.

The end of the stack is prevented from sliding from the rack by members which hold against the face of the lowermost blank.

A rounded rod 68 or bar attached at its ends to the vertical frame members extends horizontally across the face of the lowermost blank It parallel to the lower edge 12 of the blank.

The upper edge 14 of the lowermost blank is supported by a pair of floating snap clips 16 mounted on a horizontal frame member H. The clips have face pieces 18 which overlay the blank and are attachedto inclined shoulders 13 which extend back along the side of the stack. The face pieces have slots 80 through which studs 8| pass into the shoulder to hold the face'piece to the shoulder and allowing adjustment of the amount of overlay. For the most favorable operation the face piece should be adjusted to extend over the face of the blank a small distance sufficient only to prevent the blank from slipping out of its own volition. Theshoulder riding on .the side of the stack insures the same overlay of the face piece at all times. The forward portion of the lower face 82 of the shoulder is preferably shaped so it will have the same contour as the upper side of the stack when a full stack of blanks is in the rack. This lower face of the shoulder will then have an area of contact'with the upper side of the stack which is slightly inclined because of the bend of the sheets from the weight of the stack. The face of the shoulder is tapered upwardly so a new stack of blanks, when inserted, will slide under the shoulder.

A pair of pins 84 and 86 slidably extend into the horizontalframe member, the longer pin 85 having a .tension spring 88 between it and the frame member 11 urging the shoulder against'the stack. The shoulder, abutting .a large number of blanks, prevents the action of the spring from 4 having any appreciable bending effect on the blanks. A stop nut 90 abuts a sleeve 92 fixed on the frame member ll when the shoulder is in its lowermost position. The stop nut is set so the shoulder is allowed to move downwardly to a point where the lower edge of the stack will just clear the shoulder tip when a new stack is inserted causing the shoulder to ride up onto the stack edge. When the stack is inserted and strikes the bar 68 and snap clip 76 the weight will cause the blanks to bend and the shoulder will follow as the stack becomes narrower due to bending. This insures that the snap clip will always .overlay the face of the blank no matter how much the blanks bend.

A pair of resilient holders at press laterally against the stack to prevent the full weight of the stack from settling against the clips. A bolt 96 in the horizontal frame member l8 passes through a vertical slot .98 in the holder to secure the holder and allows for adjustment toward the stack. The holders are faced with resilient mate.- rial lllil such as sponge rubber to .create a holding friction between the holders and the stacker. as they press against the stack edge.

A pair of pivotal arms 802 are mounted on a shaft iii-'1 oscillated by a crank arm I at connected to a pitman 103 which is driven by a crank N0, the crank shaft H2 being rotated by the near sprocket 52 of the conveyor chain assembly.

The arms (Fig. 10) are comprised of a lower portion [[4, offset a predetermined distance from the oscillating shaft to bring the arm parallel to the lowermost sheet in upper pivotal position and to bring the arm to a horizontal position when it releases the sheet in lower pivotal posi-. tion. Into this lower portion of the arm a midsection H8 is telescopically threaded, the midsection having the end-section I20 telescopically threaded into it, the mid-section and end-section each carrying a suction cup I22. Lock nuts I24 are provided for each of the threads.

The vacuum cups I22 are each provided with holes I28 which lead through passageways in the arm, through tubes Hi? to a cam valve I36 which is shown in detail 9.

The cam valve alternately connects the vacuum tube l28 leading to the cups to a vacuum source (not shown) to grasp a blank and then vents it to atmosphere to release the blank.

The cam plate I32 is mounted on the shaft I34 and actuates a pivotal follower G35 operating a valve plunger I58 which operatesthe valve connecting the tube to the vacuum lineor'to atmosphere.

As a stack of blanks is slid into the rack, the weight of the blanks above causes the lower blanks to bend the lowermost blank supporting the greatest weight and being bent the most presenting a curved face of the lowermost blank lil'which the suction cup must contact. To grasp the blank the arms are pivotable to a position where the cups strike the lowermost blank. Warpage and bending from weight will bow out the blank causing one of the suction cups to strike the blank while the other will not make contact. To remedy this unevenness, each arm is adjustable betwee the cups and between the cups and the oscillating rod, thereby making it possible to adjust the position of the cups relative to the curvature of'the blank so all cups will strike simultaneously. This adjustment may also be used to position the cups so they willnotcom tact a score line on the blank. In additionthe cups may be tilted so their axis is 'not'parallel to the path of travel but so the cups will strike flatly against the curved blank. It will also be noted that the cups have long flexible shanks to flex to allow the cups to bend to the contour of the blank.

Extending from below the blank rack onto the delivery table of the forming machine is a pair of plates I which acts as a transfer platform on which the blank is slid, and upper shorter plates I42 provide an overhead guide at the forward end of the lower plates for holding the blanks flat. Plates I44 hold the forward end of the blank flat when it is in position on the delivery table 40. A retarding finger I46 is mounted on the rear end of each of the upper plates. The fingers are inclined so the forward edge of a blank will slide under them and press against the plates I40 to have a retarding effect on a blank being pushed under them.

Slightly below the platform is a guide rod I48, extending from the rack 64 to the delivery table 40, on which a carriage I50 is slidably mounted moving along the rod in a path lying between the platform plates. A resilient bumper I5I is mounted on the frame as a stop for the carriage.

As shown in Fig. 2, a pusher plate I52, curving upwardly and backwardly and having a center of curvature I54 below the oscillating shaft I04, is carried on the carriage. The curvature of the pusher ends in a notch I55 at its base in which the rear edge of the blank is caught for pushing forward. A blank depressor member I56 (shown in detail in Fig. 11) having depressor fingers I58 on either side, and at the top of the pusher member I52 when it is in position to receive a blank from the stack, is mounted to pivot about point I60 on the carriage, the point being below the center of curvature I54 of the pusher plate I52. The importance of the relative positions of the oscillating shaft, center of curvature of the pusher member, and the pivotal point of the depressor fingers, will be explained later in the disclosure.

The carriage is reciprocated from the blank receiving position beneath the stack to the blank delivering position adjacent the delivery table by a pivotal bell crank I62 attached to the base I64 of the depressor. The bell crank is pivoted at a point I66 below and substantially at the midpoint of linear travel of the depressor base I64. The bell crank is connected at its lower end by an intermediate link I61 to the end of a pivoting connection I68 which is mounted on the frame. A telescoping link I12 is connected to the same point on the connector link and is connected by an eccentric crank I14 to the drive shaft 20. The telescoping link expands to permit the eccentric to complete its revolution while the linkage to the carriage is locked and its full operation will be explained later.

The operation of the blank delivery mechanism is as follows: The arms I02 are pivoted by the oscillating shaft I04 to press the suction cups I22 against the lowermost blank 10 as shown by the dotted line position of Fig. 3. The vacuum valve I30 opens causing the cups to grasp the blank. The arms I02 pivot downwardly pulling the lowermost blank 10 away from the stack 62, slipping first from the clips 16. The clip shoulder 80 and the sponge rubber pads I00 allow the top of the next adjacent blank to settle lightly against the clips 16. The lowermost blank 10 then slides up over the rod 68. The clip shoulder prevents the friction of the first blank from pulling the second up over the rod. As the blank is carried pivotally downwardly, the center of the oscillating arm being above the center of curvature of the pusher plate, the path of the lower edge 12 of the blank (indicated by the broken line of Fig. 3) approaches the curved pusher plate I52. This means that the blank will clear the depressor finger but will be positioned on the platform closely adjacent to the pusher plate. When the plate starts to move forward, it will not have far to travel before contacting the blank. This is desirable for successful delivery where the pusher must have rapid movement.

When the blank is on the transfer platform I44 and the arms are in the solid line position of Fig. 3, the cups are vented to atmosphere and release the blank.

It is to be noted that" the arms for proper operation are parallel to the plane of the lowermostsheet of the stack at the uppermost pivotal position and are parallel to the plane of the platform at the lowermost pivotal position. This is accomplished by relatively determining the correct size of the suction cups, amount of offset of the lower arm and position of the oscillating shaft. The length of suction cup shank is chosen to allow the proper amount of flexing to conform to the contour of the warped blank. The position of the oscillating shaft must be such that it does not interfere with other operating parts but must be positioned so that the distances from it to the plane of the lowermost blank or to the plane of the platform are equal which is necessarily on the line bi-secting the supplement of the angle between said planes. When the length of cups has been chosen for proper fiexure, the position of the oscillating shaft is next chosen. If the position chosen is above the plane of the platform it must be rearward of the plane of the lowermost blank, and if below the platform plane it must be forward of the plane of the blank.

If the position of the oscillating shaft is above the plane of the platform, the offset distance of the lower pivot arm must be equal to the length of the suction cup plus the distance from either plane to the oscillating shaft and if the position is below the plane of the platform the offset distance must be equal to the cup length less the distance from either plane to the shaft.

Figs. 5 through 8 show a series of operating positions of the parts as the blank is flattened and positioned over the forming well. As the carriage I50 begins to move forward, as shown in Fig. 5, the base I64 of the depressor is moving upwardly,causing the fingers I58 to move downward as' well as forward with the carriage. Since the pivotal point I60 of the depressor is below the center of curvature I54 of the pusher arm, the fingers move in an arc in front of the pusher arm to contact the rear end I15 of the blank I18, as shown in Fig. 6, andpress down the rear end of the warped blank, the front end I being pushed and depressed under the re tarding spring fingers I46. If the pivotal point of the depressor were above the center of curvature of the pusher arm, the depressor fingers would have a scissors action against the pusher, pinching the blank.

As shown in Fig. 7 the forward end of the blank has been pushed down by the spring fingers and the rear end by the depressor fingers presenting a fiat blank. The flattened blank rides under the upper plates I42 to remain fiat. When the blank is completely under the upper plates I42 the depressor fingers have reached the lowermost position, as shown by the solid lines of Fig. 3.

- expands.

The fingers then begin 'pivoti-ngupward :and move to an upward receded position, shown by dotted position .0 of Fig. 3, 'to :be clear of the :descending mandrel H3, also shown dotted in'the descending sition.

It will be noted that as the rear edge of the .warped carton blank has been depressed to the :base of the pusher plate 152, it drops into the :notch 1.55 and the blank will be accurately positioned on :the delivery platform over the-forming well 142. As the distance from the notch of the pusher arm to the abutment Stop it for the blank is equal :to the width of the blank, it is evident that the blank must be flat and be positionedin thenotch at thebase of the pusher arm.

The carriage is then returned to rear position where it strikes a resilient bumper i5! stopping :the linkage which drives the carriage. At that point the telescoping link 112 begins expanding to allow the eccentric 114 to complete its rotation, permitting the other members to continue to operate. Thepusher-andfingers remain at rest while the extension link compresses and During that time the gripper arms havetime to pull down the next blank onto the platform for the next delivery stroke.

Thusit will be seen we have invented a workable mechanism for delivering at high speed .carton'blanks which have inherent carton warpage and are bent from the weight of the stack.

The machine is capable of handling successfully blankswhich -vary from warpageof varying degrees'to no warpage and will position the blanks in a hat condition and inaccurate position regardless of this variation.

While the invention is susceptible of various modifications and alternative constructions, we have shown in the drawings and have described in detail the preferred embodiment. However, it "is to be understood that we do not thereby intend to limit the inven-ion to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appendedclaims.

We claim as our invention:

1. A mechanism fordelivering a single warped blank from a stack of blanks comprising in combination a horizontal platform to which the blank is delivered, means supporting the stack of blanks at the rear end of the platform, a curved pusher armat the rear end of the platform having .its center of curvature in a direction rearward of the platform, and a pivotal blank deliveryarm movable between thestack and platform and pivoting about apoint above-said center of curvature, the are traced by'the'lower edge of the delivered blank intersecting the pusherarc.

.2. A mechanism for delivering a single warped blank from a stack comprising in combination a platform to which the blank is delivered, a ac o a s at e re r e o the p a rm. cu dsh r m at th ea o he atfor having its center of curvature in a direction rearward of the platform, a pivotal blank delivery member movable between the stack and platform, said' member pivoting about a point above said center of curvature so'the base .of 'the blank approaches the pusher as it is-placed on the platform, and a pair of fingers extending forwardrol the pusher and moving .from the top .of the pusher to the platform in an archaving'its centerbelow said center'of curvature of the pusher.

3. A mechanism fordelivering awarpedblank. comprising a Y platform on which the blank slides, means'placing the blank on theplatform, a carriage movable from the rear to the frontparallel to the platform, a curved blank pusher attached to the carriage and having its .center of curvature rearward ofthe platform, -a depressor member pivotally mounted at its midpoint on the carriage below :said center of curvature, and a link attachedto the lower end of thedepressor and pivoting about a'point below and substantially at the midpoint of the carriage stroke causing the upper end of the depressor vto-move downward toward the platform until the midstroke ofzthecarriage and .then upward from the platform .tobe clear of the blank.

4. A mechanism fordelivering a-warped blank, comprising a platform on :which the blank is pushed, means-for placing the blank on the platform, a guide ibar extending from rear to front andparallel to the platform, a carriage slidable on the bar having a curved blank pusher extending curvedly-upward above theplatform and having its center .of curvature to the rear of the platform, a depressor member pivotally mounted on .the carriage beneath said center of curvature and havin its unr rend ext nd n t the top o the pushe a when h car a e is at e rea mos position. a link w vted t h depressor and pivotally movable about a point forward and below the lower end of the depressor member at the rearmost carriage position to cause the upper end to move toward the platform as it moves forward.

5. A mechanism for delivering a single warped blank from a stack to a delivery table comprising in combination a platform adjoining the delivery table on which the blank is slid, a carriage movable along the platform to the delivery table having a pusher plate curved upwardly and rearwardly and having a depressor member adjacent the pusher plate pivotally mounted below the center of curvature of the plate, and means to pivot the depressor member downwardly and forwardly as the carriage moves to the delivery table, pressing down the rear edge of the warped blank.

HARRY K. WETHE. V ROBERT HORACE DUNCANSON.

nevertheless CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 769,92 Z h Sept- 1.3.1 4 955,112 Abrams Apr. 12, 1910 2,352,088 Evans June 20, 194; 

